Little is known regarding the process by which teens succeed or fail after treatment for alcohol abuse or their long- term clinical course. In contrast to adult findings, our current research has found that adolescents receiving alcohol treatment demonstrate developmentally related differences in the relapse process, strategies through which they successfully abstain after treatment, and clinical course for up to four years after treatment. Additionally, it has become evident, that psychiatric co-morbidity influences outcome for adolescent alcohol abusers. For example, we have found that alcohol abusing teens with concomitant conduct disorder demonstrate greater relapse rate, briefer periods of sustained abstinence, less forethought regarding relapse risk, and fewer cognitive coping strategies than alcohol abusing teens without conduct disorder. Unfortunately, theory driven research of adolescents with concomitant alcohol/drug and other mental disorders is lacking, and the specific relapse vulnerabilities and strategies for abstinence for teens with comorbid disorders are unknown. The present proposal is designed to address these two information gaps regarding adolescent alcohol abuse. Specifically, we will 1) follow, at six and eight years our sample of 250 adolescent alcohol abusers (already studied for four years) to determine the long term alcohol and drug use outcome, assess psychiatric and other life problems emerging in this sample, and examine the relationship between clinical course and adult functioning; 2) extend our research of adolescent addiction relapse to the critical area of psychiatric comorbidity to test for differences in rate, process, and circumstances of relapse and examine the applicability of current relapse models to comorbid groups of adolescents; and 3) continue our model building analyses of adolescent functioning across the four follow-up time points and replicate these using the new young adult follow-up data. Major advantages of this project are the less costly opportunity to evaluate young adult functioning of a well-described, consistently followed (four years) sample of 250 adolescent alcohol abusers, extensive research experience with the evaluation of adolescent addiction relapse making successful extension to comorbid psychiatric populations more likely, and the opportunity to explore developmentally sensitive models of alcohol abuse clinical course in an already existing data base.